The present invention is an improvement of Korean Patent Application Publication No. 2010-0105103 (Korean Patent Application No. 2009-0023951) (entitled axial turbine) filed by the applicant.
As generally known in the art, a turbine is a machine for converting the energy of a fluid such as water, gas, and steam into mechanical work, and is characterized in that the turbine is rotated. Generally, a turbo machine in which several blades or wings are implanted on a circumference of a rotating body to be rotated at a high speed by ejected steam or gas is referred to as a turbine. A water power turbine drops water of a high head such that the water passes through a runner to convert the energy of the water into mechanical work, and a steam turbine ejects steam of a predetermined pressure from a nozzle such that the steam is applied to blades to use stream energy to rotate the blades. Turbines include an impulse turbine, a submerged propelling turbine, and a repulsive turbine, and a combined gas turbine in which the advantages thereof are combined. A gas turbine uses the energy of gas with a high temperature and a high pressure, and an air turbine uses energy of compressed air of a high pressure. All turbines are important as they provide industrial power. Steam turbines are used to drive a generator in nuclear power plants, and also thermal power plants, and wind power turbines are used to move a generator in water power plants.
Meanwhile, a multistage turbine refers to a turbine in which gas or steam is divided into several stages to be expanded, and several stages including a nozzle, a fixed blade, and a rotary blade are combined.
However, the gas turbine has a low thermal efficiency and a high lower consumption, and the structure of rotating bodies are complex and large-sized so that a wide axial space is necessary and the gas turbine cannot be easily installed.
[Patent Document]
In order to solve the above-mentioned problems, the applicant filed Korean Patent Application Publication No. 2010-0105103 (Korean Patent Application No. 2009-0023951) (entitled multistage axial turbine). That is, according to the related art, as shown in FIGS. 1A, 1B, and 1C, the axial turbine includes a housing 20 formed such that a fluid may flow therein, a rotary shaft 30 rotatably installed in the housing 20, a front impeller 40 installed in the rotary shaft 30 and having a plurality of through-holes 41 through which the fluid passes, and rear impellers 50 fixed to the rotary shaft 30 to be located at a rear side of the front impeller 40, for generating rotating power by guiding a flow of the fluid. Constituent elements of the axial turbine configured as described above will be described as follows. The housing 20 includes a cylindrical body 22 opposite sides of which are opened such that a fluid that is a gas or a liquid may be introduced into the body 22, a front cover 21 having an inlet 24 through which the fluid is introduced into the housing 20 and covering a front side of the body 22, and a rear cover 23 covering a lower side of the body 22 and having a discharge hole 25 from which the fluid in the housing 20 is discharged.
The housing 20 configured as described above will be described in more detail as follows. The front cover 21 and the rear cover 23 have disk shapes having an outer diameter corresponding to an outer diameter of the housing 20. Through-holes 41 are formed at the centers of the front cover 21 and the rear cover 23 such that the rotary shaft 30 may be inserted into the through-holes 41. It is preferable that bearings 26 are installed in the through-holes of the front cover 21 and the rear cover 23 such that the rotary shaft 30 may be easily rotated. A plurality of through-holes are formed at peripheries of the front cover 21 and the rear cover 23 such that the front cover 21 and the rear cover 23 may be coupled to the housing 20 by bolts. The body 22 includes an accommodating space in which a front impeller 40 and a plurality of rear impellers 50 may be accommodated. An impeller fixing recess 27 to which the front impeller 40 may be fixed is formed on an inner peripheral surface of a front end of the body 22. The rotary shaft 30 has a rod shape, and opposite ends of the rotary shaft 30 are rotatably supported by the front cover 21 and the rear cover 23 covering opposite side surfaces of the housing 20. The front impeller 40 has a disk-shaped structure, and since a fluid of a high temperature and a high pressure may be introduced, it is preferable that the front impeller 40 is formed of a heat-resistant material. Although not shown, a periphery of the front impeller 40 is fixed to the impeller fixing recess 27 in the housing 20 by fixing bolts. A through-hole is formed at a central portion of the front impeller 40 such that the rotary shaft 30 is inserted into the through hole to be rotatably supported by the through-hole. It is preferable that bearings 26 are installed in the through-holes of the front cover 40 such that the rotary shaft 30 may be easily rotated. A plurality of through-holes 41 passing through the front impeller 40 inclinedly are formed in the front impeller 40 such that the fluid introduced into the housing 20 passes through the through-holes 41 to be guided into a guide groove 51 of the rear impeller 50.
The through-holes 41 of the above-mentioned front impeller 40 will be described in detail as follows. Each of the through-holes 41 of the front impeller 40 includes a vertical portion 42 vertically formed from a front side surface of the front impeller 40 to an interior of the front impeller 40, and a bending portion 43 communicated with the vertical portion 42 and bent to correspond to a location of the guide groove 51 of the front impeller 50. Although not shown, unlike the embodiments of the present invention, the vertical portion 42 and the bending portion 43 of the front impeller 40 are not divided but integrally formed to be inclined in a direction corresponding to a rotation direction of the rotary shaft 30.
Meanwhile, although it has been described that a row of through-holes 41 are formed along a circumferential direction of the front impeller 40, the number of the arranged through-holes 41 is not limited to the shown example but a plurality of rows of through-holes may be formed according to a flow rate and a pressure of the fluid.
However, the technology according to the related art also has the following problems. That is, since the turbine does not include a submerged turbine and a colliding turbine, it cannot be selectively used in correspondence to a field situation. Further, the technology according to the related art cannot maximize an angle efficiency of a turbine wing. In addition, the technology cannot prevent loss of flow rate. Furthermore, in the technology according to the related art, since a pressure of a fluid pushes down the wings, the wings may be damaged and distance efficiency cannot be maximized. In addition, the technology according to the related art cannot solve the problem of lowering a temperature of the fluid. Finally, the technology according to the related art fails to solve the problems of applying a load to a pressure of the wings.